Re: [PATCH] char/tty_io: fix legacy pty name when more than 256 ptydevices are requested

From: H. Peter Anvin
Date: Thu Sep 10 2009 - 15:21:12 EST


On 09/10/2009 12:12 PM, Mauro Carvalho Chehab wrote:
>
> +1. Reusing the namespace after tty[p-za-e][0-9a-f] doesn't seem to be good, IMHO.
>

I think it's better to extend the strings with the current prefixes than
to burn the virgin ttyf* prefix.

> In the case of the BSD sockets, the patch is not just an userless fix. This is
> interesting when some applications are ported from other Unix'es and still uses BSD
> pty's, since several other Unix flavors were defining a higher namespace size.
>
> For example, on zOS Unix, a pty device seems to allow up to 10.000 pty numbers (in the
> specific case of zOS Unix, they seem to be defined as /dev/[pt]typ[0-9]...) as shown at:
> www.redbooks.ibm.com/redbooks/pdfs/sg245228.pdf
>

Yes, but you have to port the application *anyway* do deal with the
namespace. BSD tty allocation is done largely by each application,
which makes it even worse. Furthermore, there is the static allocation
issue, so unless there is a concrete application which needs this *and*
cannot be ported to Unix98 ptys (which is the Right Thing[TM] to do) I
think Alan is right.

-hpa
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